As author Robert C. Gallagher observes, “Change is inevitable – except from a vending machine.” And so it comes as no surprise that paid search engines are changing too. The biggest change is one of the most fundamental, affecting which paid ads are shown first in the results. The tried-and-true high bidder auctions, pioneered by Overture (later acquired by Yahoo), are being phased out in favor of hybrid auctions, introduced by Google.

High-bidder auctions are just what they sound like – the search marketer who bids the highest per-click amount for each search keyword gets the top spot in the paid search rankings. But high-bidder auctions are starting to seem so 20th century.

The new thing is hybrid auctions, which set the paid search rankings based on a combination of the bid, the clickthrough rate and sometimes other factors. For example, if one search marketer bids $2 per click to show an ad with a 1 percent clickthrough rate, another bidder could outrank the first with a lower bid – perhaps by bidding $1 for an ad with a 3 percent clickthrough rate. In a high-bidder auction, the $2 bidder would always rank higher than the $1 bidder.

Google has been using hybrid auctions for years, but until recently, all other paid search engines were the high-bidder type. That’s all changing now. Earlier this year, MSN Search introduced new paid search technology that uses a hybrid auction. Yahoo has announced plans to follow suit late this year or early next year. Given Google’s longstanding use of hybrid auctions, the changes at MSN and Yahoo will transform the paid search industry, and nearly a whopping 97 percent of all paid search queries will use hybrid auctions.

Hybrid auctions usually provide more relevant results to searchers, because the most-clicked ads tend to rise to the top of the rankings. And hybrid auctions make the search engines more money, because the combination of clickthrough rate and bid price maximizes the total fees paid by search marketers.

More Complex Planning

If you’re a search marketer accustomed to planning paid search campaigns for high-bidder auctions, hybrid ones bring you some new challenges. With a high-bidder auction, you can see what your competitors are bidding at all times, and can take an educated guess as to what bid could get you ranked No. 1, for example.

Hybrid auctions, however, demand pure guesswork; not only don’t you know your competitors’ clickthrough rate, but you don’t even know your own, so you can’t predict where your ad will land no matter what the bid. Without that information, you can neither project the number of clicks your campaign will get, nor the amount you’ll pay in total, which hamstrings your ability to plan your paid search campaigns.

Google and MSN could help predict the number of clicks you’ll get with your bid, but they don’t, instead merely projecting the number of clicks to expect with an average bid. If your bid is higher (or lower) than average, you’re out of luck.

In contrast, Yahoo has publicly stated that they will provide predictive information based on your bid when they convert to a hybrid system, so we may be able to use Yahoo to help plan campaigns.

Simpler Operations

While hybrid auctions can pose new campaign planning issues, they also make operating your paid search campaigns far easier than high-bidder systems do.

To understand how much is changing, we need to remind ourselves of the work required to manage high-bidder campaigns. The very predictability of high-bidder auctions that aids campaign planning also makes operations tougher than with hybrid approaches. Because changing your bid in a high-bidder auction directly changes the search rankings, search marketers can use bidding tricks against their competitors to manipulate those rankings.

These high-bidder tricks include bid jamming (intentionally bidding 1 cent below a competitor’s bid to force them to spend as much as possible); gap surfing (bidding 1 cent more than a competitor to steal a higher spot); and friendly URL (bidding just under a specific opponent to avoid a bidding war).

Search marketers managing campaigns in high-bidder auctions must be aware of these techniques and must use them for highly competitive keywords. These techniques require constant monitoring and tinkering, raising operational costs for high-bidder campaigns.

In contrast, none of these tactics are needed for hybrid auctions, because the rankings can’t be changed simply with a new bid. And because clickthrough rates can’t be adjusted at will the way a bid can be, hybrid auctions are far less volatile than high-bidder auctions. The combination of fewer bidding tactics and less volatility means that search marketers can spend less time monitoring every ranking fluctuation.

A New Fraud

But all is not rosy. Search marketers are familiar with click fraud, but hybrid auctions have spawned a new kind of fraud, called impression fraud.

Impression fraud is almost the opposite of click fraud. With click fraud, competitors or unscrupulous search partners use low-paid workers or automated bots to click on paid search ads, draining the victim’s search marketing budget. Impression fraud occurs when competitors enter search terms to display your ads and then don’t click on them.

Confused? Stay with me now, because this is a bit tricky. Because hybrid auctions consider clickthrough rate in their rankings, anything that lowers your clickthrough rate helps your competitors. So, when they cause your ad to be shown and then don’t click on it, your clickthrough rate declines, which lowers your rankings (or forces you to bid higher to retain your ranking). It may scare you that some folks have nothing better to do with their time than to dream up such schemes, but it’s apparently the case.

While some observers estimate click fraud to affect as much as 20 percent of all paid search clicks, no one knows how rampant impression fraud may be. Because impression fraud cannot enrich anyone, it is likely less prevalent than click fraud, but its rise demonstrates how every change in search technology has unintended effects.

Despite the specter of impression fraud, the shift to hybrid auctions is generally a boon to search marketers, by making campaigns less work to monitor and operate, even if they are more difficult to plan for. The less time you spend in short-term bidding tactics, the more effort you can devote to improving your clickthrough and conversion rates and finding new keywords your competitors have not yet discovered. It’s better to focus on being more effective than more efficient, and hybrid auctions help you do that.

MIKE MORAN is an IBM Distinguished Engineer and the Manager of ibm.com Web Experience. Mike is also the co-author of the book Search Engine Marketing, Inc. and can be reached through his website (MikeMoran.com).